Naoyuki Harada

While many studies have been done on triplet-triplet annihilation-based photon upconversion (TTA-UC) to produce visible light with high efficiency, the efficient TTA-UC from visible to UV light, despite its importance for a variety of solar and indoor applications, remains a challenging task. Here, we report the highest visible-to-UV TTA-UC efficiency of 20.5 % based on the discovery of an excellent UV emitter, 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (TIPS-Nph). TIPS-Nph is an acceptor wi

Abstract An efficient synthesis of various chloromethyl esters of the blocked amino acids, very useful reagents for prodrug, are described.

Abstract While many studies have been done on triplet–triplet annihilation‐based photon upconversion (TTA‐UC) to produce visible light with high efficiency, the efficient TTA‐UC from visible to UV light, despite its importance for a variety of solar and indoor applications, remains a challenging task. Here, we report the highest visible‐to‐UV TTA‐UC efficiency of 20.5 % based on the discovery of an excellent UV emitter, 1,4‐bis((triisopropylsilyl)ethynyl)naphthalene (TIPS‐Nph). TIPS‐Nph is an ac

Nonsaturated pinning characteristic and elastic and plastic properties of a fluxoid lattice are measured by an ac inductive method for superconducting Nb–Ta tapes with normal Nb 2 N precipitates. The interaction distance proportional to a yield strain of the fluxoid lattice is shown to be approximately constant except in the vicinity of the upper critical field, indicating that the fluxoid lattice is stabilized by strong pinning interactions by normal precipitates. The dependence of the pinning

Various kinds of water-soluble 9-acyloxyellipticine derivatives were synthesized in a search for compounds with potent antitumor activity. Antitumor activities against several tumors in mice (P388 leukemia, colon 26, Lewis lung carcinoma and B16 melanoma) were evaluated by using intravenous administration. Many compounds exhibited good antitumor activities; in particular, the glutarate derivative (5o) showed potent antitumor activity. This compound (5o) may be converted to 9-hydroxyellipticine (

Various kinds of water-soluble quaternary salts of 2-(2'-oxoalkoxy)-9-hydroxyellipticines were synthesized in a search for compounds with potent antitumor activity and low toxicity. Some compounds exhibited more potent antitumor activities than elliptinium (1) and SUN 4599 (3). In particular, 2-(3'-methoxy-2'-oxopropanoxy)-9- hydroxy-5,11-dimethyl-6H-pyrido[4,3-b]carbazolium bromide (4d) showed potent antitumor activities against P388 leukemia, colon 26, and Lewis lung carcinoma.

Jelly-roll Nb/sub 3/Al wires with a Nb matrix were ohmically-heated to maximum temperatures ranging from 1800 to 2300/spl deg/C in vacuum in order to optimize the ohmic-heating conditions and to investigate the superconducting properties for this transformation method. The diameters of these wires were 0.80-1.34 mm. Surface temperature at the central point of the sample was measured by a photodiode during rapid ohmic-heating. After the surface temperature reached a maximum, the sample was quench

In an attempt to improve the effectiveness and bioavailability of 6-mercaptopurine, various kinds of water-soluble analogues, such as 6-S-aminoacyloxymethyl mercaptopurine derivatives (3a--m) and 6-S,9-disubstituted derivates (7a,b and 9a,b), were synthesized. These compounds were evaluated for activity to augment antitumor immunity by using a double grated tumor system. Antitumor activities against solid tumors (sarcoma 180 and colon 26) were also evaluated. Many compounds exhibited potent acti